The present invention relates to explosive devices such as mines which are situated in a marine environment, more particularly to methods and apparatuses involving the anticipation, recognition or avoidance of underwater mines and minefields.
A mine is an explosive device which is usually concealed either underground or underwater, and which is used primarily by military forces for defensive purposes. Mines generally are difficult to detect and thus pose great threats to troops and ships. Most mines are xe2x80x9cindependent minesxe2x80x9d inasmuch as they are not controlled by the user after laying; they permit the defending military force to concentrate its personnel elsewhere, since the mines, once laid, do not require human maintenance or operation.
Mines typically are self-contained devices which include an explosive capability and a detonator (a firing mechanism for triggering the mine explosion), and which explode when touched by or approached by a target. xe2x80x9cMinefieldsxe2x80x9d are areas where mines have been placed. Generally, there are two categories of mines, based on their situation, viz., xe2x80x9cland minesxe2x80x9d and xe2x80x9cunderwater mines.xe2x80x9d
A typical land mine comprises an explosive charge buried just below the surface of the ground. Land mines can be set to fire, for example, in response to weight (e.g., of vehicles or troops) thereon, or upon the passage of time, or via remote control. xe2x80x9cAntipersonnel minesxe2x80x9d are designed to target people. xe2x80x9cAntitank minesxe2x80x9d are designed to target tanks and other land vehicles.
Underwater mines are synonymously referred to as xe2x80x9cwater mines,xe2x80x9d xe2x80x9csubmarine mines,xe2x80x9d xe2x80x9csea minesxe2x80x9d or xe2x80x9cnaval mines.xe2x80x9d As used herein, the terms xe2x80x9cwater mine,xe2x80x9d xe2x80x9cunderwater mine,xe2x80x9d xe2x80x9csubmarine mine,xe2x80x9d xe2x80x9csea minexe2x80x9d and xe2x80x9cnaval minexe2x80x9d are considered interchangeable; any of these terms broadly represents a mine which is situated in or on water or contiguously with respect to water or which otherwise bears physical or functional relation to a water environment. A typical underwater mine comprises an explosive charge positioned underwater and set to fire in response to the presence of a marine vehicle (e.g., a ship or submarine) in contact therewith or in proximity thereto. Underwater mines are generally laid in the water for purposes of damaging or sinking ships or of deterring ships from entering an area.
xe2x80x9cMoored minesxe2x80x9d are underwater mines having positive buoyancy, typically held below the water surface at a preselected depth by a mooring (e.g., cable) attached (e.g., tethered) to an anchor (e.g., on a sea bottom). xe2x80x9cBottom minesxe2x80x9d are underwater mines having negative buoyancy and resting on a seabed (e.g., at the bottom of relatively shallow water). xe2x80x9cFloating minesxe2x80x9d are underwater mines which are not entirely underwater but are visible on the surface.
Underwater mines are triggered either by direct contact or by indirect influence. When an underwater mine is triggered, an expanding gas sphere caused by the explosion sends shock waves through the water, these shock waves having deleterious effects on the nearby target marine vessel. xe2x80x9cContact minesxe2x80x9d are actuated as a result of physical contact between the target ship and the mine""s casing or one or more of the mine""s appendages (e.g., rods or antennae protruding from the mine""s surface). xe2x80x9cInfluence minesxe2x80x9d are actuated either as a result of sensing an xe2x80x9cinfluence fieldxe2x80x9d emanating from the target marine vessel, or as a result of the target marine vessel""s intrusion within an xe2x80x9cinfluence fieldxe2x80x9d emanating from the mine. Generally, influence mines sense changes in physical patterns in surrounding water, such as pertaining to magnetic fields (xe2x80x9cmagnetic minesxe2x80x9d), pressure change (xe2x80x9cpressure minesxe2x80x9d) or sound waves (xe2x80x9cacoustic minesxe2x80x9d).
An important aspect of naval defense involves the assessment of various regions of the world wherein the presence of underwater mines constitutes a threat to vehicles navigating such waters. Currently, littoral mine threat zones have to be plotted manually from navigational charts. This is a time-consuming and error-prone task. It would be desirable to avail of a more efficient strategy or approach for evaluating mine threats to marine vessels.
In view of the foregoing, it is an object of the present invention to provide method and apparatus for effectively and expeditiously assessing, within a particular geographical area, the existence of navigational risk associated with underwater mine capability.
It is a further object of the present invention to provide, in association with accomplishing same, method and apparatus for selecting such particular geographical area from among a number of geographical areas or from a larger geographical area which encompasses said particular geographical area.
In accordance with many embodiments of the present invention, a method is provided for displaying data pertaining to water mine threat on a display screen of a computer. The inventive method comprises: accessing (e.g., acquiring or gaining access to) information relating to the topography of a region which includes at least one body of water; selecting a water depth below which the water mine threat is considered an insignificant water mine threat and above which the water mine threat is considered a significant water mine threat; and, displaying a map of the region which exhibits at least one of the insignificant water mine threat and the significant water mine threat.
Typical inventive practice provides that if the map exhibits both the insignificant water mine threat and the significant water mine threat, the map exhibits contrastingly, in terms of geographical extent or scope, the insignificant water mine threat versus the significant water mine threat. If the region includes one or more land portions, and if the map exhibits the insignificant water mine threat, the map exhibits contrastingly the insignificant water mine threat versus the one or more land portions. If the region includes one or more land portions, and if the map exhibits the significant water mine threat, the map exhibits contrastingly the significant water mine threat versus the one or more land portions. If the region includes one or more land portions, and if the map exhibits both the insignificant water mine threat and the significant water mine threat, the map exhibits contrastingly the insignificant water mine threat versus the significant water mine threat versus the one or more land portions; that is, the insignificant water mine threat, the significant water mine threat and the nonexistent water mine threat (associated with the one or more land portions) are shown contrastingly with respect to each other. In other words, generally according to the present invention, the three main mine threat categoriesxe2x80x94namely, xe2x80x9cinsignificantxe2x80x9d (or inconsequential, negligible, inconsiderable, insubstantial, etc.), xe2x80x9csignificantxe2x80x9d (or consequential, considerable, substantial, etc.) and xe2x80x9cnonexistentxe2x80x9dxe2x80x94if and to the degree that they are present in the selected geographical region, are shown in mutually contrasting fashion.
Further provided in accordance with the present invention is a computer program product for use in a computer system having a central processor for implementing graph display management on a user interface display screen. The computer program product enables visual representation of a geographical area in terms of explosive threat such as mine threat to marine navigation. The present invention""s computer program product comprises: a recording medium; means, recorded on the recording medium, for obtaining data pertaining to the geographical area from a geographical database, the data including information pertaining to the terrain of the geographical area; means, recorded on the recording medium, for choosing at least one safe-depth, each said safe-depth at least approximately being the maximum marine depth beyond which a mine threat to a contemplated marine vessel is considered negligible; and means, recorded on the recording medium, for graphically displaying the geographical area as indicative of mine threat sectionalization as a function of at least one safe-depth. The mine threat sectionalization includes at least one type of zone selected from the group consisting of land mass zone, mine threat zone and mine safety zone. The mine threat zone is at least substantially characterized by a marine bed which is shallower than the safe-depth. The mine safety zone is at least substantially characterized by a marine bed which is deeper than the safe-depth.
Further provided in accordance with the present invention is a system for visualizing navigational risk associated with water mine capability which may exist in a geographical region which includes water. The inventive system comprises: means for accessing information relating to the topography of the region; means for selecting a delimitative depth of the water, wherein at water mine situation depths greater than the delimitative depth the navigational risk is deemed an inconsequential risk, and wherein at water mine situation depths lesser than the delimitative depth the navigational risk is deemed a consequential risk; and means for displaying a map of the region, wherein the map illustrates at least one of the inconseqential risk and the consequential risk, and wherein when the map illustrates both the inconsequential risk and the consequential risk, the map illustrates the inconsequential risk and the consequential risk in contrast to each other. According to frequent inventive practice, the subject region includes not only water but also land; hence, typically according to this invention, when the map illustrates the inconsequential risk, the map illustrates the land and the inconsequential risk in contrast to each other, and when the map illustrates the consequential risk, the map illustrates the land and the consequential risk in contrast to each other. Many inventive embodiments of a system for visualizing navigational risk further comprise means for selecting the geographical region, for instance via latitude and longitude, or from a preconceived menu of plural regions.
According to many embodiments of the present invention, speedy visualization is achievable of the location or locations of mine threat to naval vessels in any littoral area, worldwide. For typical inventive embodiments, the mine threat display is based on a particular vessel""s xe2x80x9csafe-depthxe2x80x9d against a particular mine. The xe2x80x9csafe-depthxe2x80x9d is the demarcative water depth whereby the marine vessel is considered threatened by an underwater mine placed above the demarcative water depth, and whereby the marine vessel is considered unthreatened by an underwater mine placed below the demarcative water depth. In usual inventive practice, the safe-depth depends on the underwater relief of the geographical area in question, since the underwater mine is presumed to be rather closely situated with respect to the floor of the water body (e.g., ocean, sea, gulf, bay, harbor, river, etc.). Frequently, the geographical region of interest is at, near or along a coastline of a land mass; hence, according to typical inventive practice, it will frequently be the case that the geographical region of interest encompasses both (i) one or more land areas and (ii) one or more water areas.
The present invention, in some of its preferred embodiments, enables rapid visualization of sea mine threat zones anywhere in the world. According to typical embodiments of the present invention, area selection is accomplished through latitude and longitude entry with a two-dimensional preview display of the selected area. The selected area is extracted from a world elevation database and displayed as a three-dimensional filled polygonal mesh with one or more color-coded threat zones (e.g., mine threat zones versus mine safety zones); as desired, this three-dimensional image can be rotated, zoomed and/or shifted (e.g., using a mouse and/or keypad).
Many inventive embodiments provide for a computer-implemented regime according to which a two-dimensional image can initially be displayed, and a three-dimensional image can subsequently be displayed. For instance, the inventive practitioner can have the opportunity to more accurately define (e.g., xe2x80x9czero in onxe2x80x9d or xe2x80x9cfine-tunexe2x80x9d) the geographical region of interest, re-selecting and re-displaying the contemplated region until he or she is satisfied with its precise location and limits. When satisfied, the inventive practitioner can switch from two-dimensional image mode to three-dimensional image mode. The previously two-dimensional image of the satisfactorily defined region can then be rendered in a three-dimensional image form which is adjustable (e.g., rotatable to different perspectives or viewpoints) so as to enhance the inventive practitioner""s understanding of the mine threat characteristics of the region. At any time or at a moment""s notice, the inventive practitioner can shift his focus to an entirely different part of the world, whether in the same or opposite hemisphere. The achievement of three-dimensional visualization or the provision of three-dimensional visualization capability may not be necessary, depending on the inventive embodiment or application; that is, a two-dimensional image of a given region may suffice for purposes of imparting requisite mine threat information.
There are several advantages of the inventive methodology over previous methodologies. An inventive program can enable extremely rapid construction of the threat zone visualization for any area in the world. Moreover, the present invention""s visualization can be in three dimensions, allowing for qualitative as well as quantitative evaluations of threat zone boundaries and safe navigation areas. In addition, the present invention""s user interface dialog with its embedded preview display can enable the user to fine-tune the selection area (e.g., in two dimensions) before it is visualized in three dimensions. Furthermore, the inventive use of a world database is less error-prone than manually looking up depth values on a navigational chart.
Other objects, advantages and features of this invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.